The invention relates to a wheel for rolling guides for drawers and other such pull-out furniture parts, whose body made from a hard plastic of good stability of shape and mounted for rotation on an axle has a circumferential, groove-like gap in its rim, in which a tire of resiliently deformable material, preferably an elastomeric plastic, projecting slightly above the tread of the wheel body, is disposed.
In drawer guides which are equipped with such wheels (German Federal Gebrauchsmuster 71 29 122), the resiliently deformable tires serve to suppress the rolling noise made when the wheel rims roll on the guide rails and running rails of the drawer guide. To prevent the resiliently deformable wheel tires from permanently deforming in the course of time due to the pressure of the weight of the drawable cabinet part, especially when the drawer guide is in the closed position, it has been found desirable to relieve the tires of the load by appropriately shaping the running surfaces of the guide rails and/or running rails in the areas associated with the end position of the wheels (German Federal Patent Disclosure document 35 21 860). The tires are formed in the known wheels by rubber rings disposed in circumferential grooves in the wheels. It has been found, however, that these resilient tires, especially in the case of more heavily loaded wheels, tend in the course of time to stretch, in which case the danger then exists that the tires may come out of the grooves.
It is the object of the invention, accordingly, to improve the known wheels such that the tires will be held reliably in the corresponding groove-like gap in the wheel body, even in the case of heavily loaded drawer guides, and thus assure the desired quieting over the entire life of the piece of furniture.
Setting out from a wheel of the kind mentioned above, this object is achieved in accordance with the invention in that, in at least one of the confronting side surfaces and/or in the circumferential bottom surface of the groove-like gap, at least one, preferably more, indentations are provided in which the material of the tire, put into fluid form and then converted to the resiliently deformable state, interlockingly engages, and that a hole for the injection of the still fluid tire material opens in a outside face of the side walls of the wheel body of good stability of shape, while its other end opens in the interior of the groove-like gap. In a wheel thus configured, the tire is held interlockingly in the groove-like gap of the wheel body, so that any loosening is avoided, along with the danger that the tire might stretch and fall out of the gap.
The indentation or indentations in the side wall or walls and/or bottom surface of the groove-like gap run preferably in the opening direction of the parts of the wheel body injection mold which forms the groove-like gap, and they are formed so that they have no undercut interfering with the opening of the mold. Thus it is possible to injection-mold the wheel body, including the groove-like gap, in one piece. The tire is then installed by injecting still-fluid material forming the tire into the injection hole until the groove-like gap is completely filled. It is clear that during the injection process the gap must be closed on the wheel rim by a mold part completely surrounding it, such that the desired external shape of the tire, protruding slightly above the rim surface of the wheel, is formed.
If the indentations are provided in one or both side walls of the groove-like gap, it is recommended that they be configured as parallel grooves running in a straight line in the mold-opening direction. A configuration has proven particularly desirable in which the grooves have a triangular or trapezoidal cross section flaring from the bottom of the groove.
If the indentations, alone or in addition to the indentations in the side walls, are provided in the bottom surface of the circumferential gap, it is recommended to configure them as grooves running parallel to the axis of rotation of the wheel, with their ends pointing in the direction in which the associated part of the mold opens.
These grooves, too, can then have a cross section flaring from the groove bottom in the direction in which the mold opens.
Alternatively or additionally, the indentations can be formed also by at least one through-bore provided in the bottom surface of the circumferential gap, running in the direction in which the mold opens, and opening at both ends in the bottom surface, while the injection hole(s) then open at their wheel-body-interior end in the through-bores or in one of the latter.